By the middle of this book I wanted to stab my eyes out, but it got a little better by the end.
What I liked: Mercea, once I figured out who, exactly he was and his relationship to Cassie. I mean, what's not to like about a hot vampire, right? The premise is interesting enough, and I mostly like the MC.
What I didn't like: Too many characters, names and races thrown in all at once. Most of the book I was flipping pages to find out who everyone was and why I was supposed to care.
The pace was brutal. I think there might have been a total of ten scenes in the entire book. I'd get one line of dialogue, then pages of explanation before the next line would come. I found it extremely hard to follow the scenes because of it and I grew bored, skipping pages and pages at a time to find the next bit of dialogue so I could keep up.
Also, the time travel thing opens up a whole can of issues that prevented me from suspending my disbelief. Like, for example, why would the mages go back in time to prevent a vampire being made when they could just prevent Cassie from being born and solve all of the issues? A lot of it requires the reader to not think beyond the story, and I'm too much of a scientist for that.
If you don't mind slow, detailed books, you might like this one a lot, but it wasn't for me.